Add support for SLCAN
* Adding support for SLCAN type interfaces
* Made some of the formatting more consistent
Bug: 142656299
Test: Manually with canhalctrl, canhaldump, and canhalsend
Change-Id: Ifa4c234beb75f8a0ea93bfd75555c5ed8d68dca4
diff --git a/automotive/can/1.0/default/CanBusSlcan.cpp b/automotive/can/1.0/default/CanBusSlcan.cpp
new file mode 100644
index 0000000..7dce838
--- /dev/null
+++ b/automotive/can/1.0/default/CanBusSlcan.cpp
@@ -0,0 +1,166 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "CanBusSlcan.h"
+
+#include <android-base/logging.h>
+#include <libnetdevice/can.h>
+#include <libnetdevice/libnetdevice.h>
+
+#include <net/if.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <termios.h>
+
+namespace android {
+namespace hardware {
+namespace automotive {
+namespace can {
+namespace V1_0 {
+namespace implementation {
+
+namespace slcanprotocol {
+static const std::string kOpenCommand = "O\r";
+static const std::string kCloseCommand = "C\r";
+static constexpr int kSlcanDiscipline = N_SLCAN;
+static constexpr int kDefaultDiscipline = N_TTY;
+
+static const std::map<uint32_t, std::string> kBitrateCommands = {
+ {10000, "C\rS0\r"}, {20000, "C\rS1\r"}, {50000, "C\rS2\r"},
+ {100000, "C\rS3\r"}, {125000, "C\rS4\r"}, {250000, "C\rS5\r"},
+ {500000, "C\rS6\r"}, {800000, "C\rS7\r"}, {1000000, "C\rS8\r"}};
+} // namespace slcanprotocol
+
+/**
+ * Serial Line CAN constructor
+ * \param string uartName - name of slcan device (e.x. /dev/ttyUSB0)
+ * \param uint32_t bitrate - speed of the CAN bus (125k = MSCAN, 500k = HSCAN)
+ */
+CanBusSlcan::CanBusSlcan(const std::string& uartName, uint32_t bitrate)
+ : CanBus(), mUartName(uartName), kBitrate(bitrate) {}
+
+ICanController::Result CanBusSlcan::preUp() {
+ // verify valid bitrate and translate to serial command format
+ const auto lookupIt = slcanprotocol::kBitrateCommands.find(kBitrate);
+ if (lookupIt == slcanprotocol::kBitrateCommands.end()) {
+ return ICanController::Result::BAD_BAUDRATE;
+ }
+ const auto canBitrateCommand = lookupIt->second;
+
+ /* Attempt to open the uart in r/w without blocking or becoming the
+ * controlling terminal */
+ mFd = base::unique_fd(open(mUartName.c_str(), O_RDWR | O_NONBLOCK | O_NOCTTY));
+ if (!mFd.ok()) {
+ LOG(ERROR) << "SLCAN Failed to open " << mUartName << ": " << strerror(errno);
+ return ICanController::Result::BAD_ADDRESS;
+ }
+
+ // blank terminal settings and pull them from the device
+ struct termios terminalSettings = {};
+ if (tcgetattr(mFd.get(), &terminalSettings) < 0) {
+ LOG(ERROR) << "Failed to read attrs of" << mUartName << ": " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // change settings to raw mode
+ cfmakeraw(&terminalSettings);
+
+ // disable software flow control
+ terminalSettings.c_iflag &= ~IXOFF;
+ // enable hardware flow control
+ terminalSettings.c_cflag |= CRTSCTS;
+
+ struct serial_struct serialSettings;
+ // get serial settings
+ if (ioctl(mFd.get(), TIOCGSERIAL, &serialSettings) < 0) {
+ LOG(ERROR) << "Failed to read serial settings from " << mUartName << ": "
+ << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+ // set low latency mode
+ serialSettings.flags |= ASYNC_LOW_LATENCY;
+ // apply serial settings
+ if (ioctl(mFd.get(), TIOCSSERIAL, &serialSettings) < 0) {
+ LOG(ERROR) << "Failed to set low latency mode on " << mUartName << ": " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ /* TCSADRAIN applies settings after we finish writing the rest of our
+ * changes (as opposed to TCSANOW, which changes immediately) */
+ if (tcsetattr(mFd.get(), TCSADRAIN, &terminalSettings) < 0) {
+ LOG(ERROR) << "Failed to apply terminal settings to " << mUartName << ": "
+ << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // apply speed setting for CAN
+ if (write(mFd.get(), canBitrateCommand.c_str(), canBitrateCommand.length()) <= 0) {
+ LOG(ERROR) << "Failed to apply CAN bitrate: " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // set open flag TODO: also support listen only
+ if (write(mFd.get(), slcanprotocol::kOpenCommand.c_str(),
+ slcanprotocol::kOpenCommand.length()) <= 0) {
+ LOG(ERROR) << "Failed to set open flag: " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // set line discipline to slcan
+ if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kSlcanDiscipline) < 0) {
+ LOG(ERROR) << "Failed to set line discipline to slcan: " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // get the name of the device we created
+ struct ifreq ifrequest = {};
+ if (ioctl(mFd.get(), SIOCGIFNAME, ifrequest.ifr_name) < 0) {
+ LOG(ERROR) << "Failed to get the name of the created device: " << strerror(errno);
+ return ICanController::Result::UNKNOWN_ERROR;
+ }
+
+ // Update the CanBus object with name that was assigned to it
+ mIfname = ifrequest.ifr_name;
+
+ return ICanController::Result::OK;
+}
+
+bool CanBusSlcan::postDown() {
+ // reset the line discipline to TTY mode
+ if (ioctl(mFd.get(), TIOCSETD, &slcanprotocol::kDefaultDiscipline) < 0) {
+ LOG(ERROR) << "Failed to reset line discipline!";
+ return false;
+ }
+
+ // issue the close command
+ if (write(mFd.get(), slcanprotocol::kCloseCommand.c_str(),
+ slcanprotocol::kCloseCommand.length()) <= 0) {
+ LOG(ERROR) << "Failed to close tty!";
+ return false;
+ }
+
+ // close our unique_fd
+ mFd.reset();
+
+ return true;
+}
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace can
+} // namespace automotive
+} // namespace hardware
+} // namespace android